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HISTORY OF SANTUBONG, SARAWAK. 21 
dignity of a new genus by Mr. Shelford who called it Miro- 
blatta petrophila. 
The invertebrate life of the sea shore could provide an 
endless source of interest in its myriads of tiny crabs which 
scuttle away at every sound, and in its boring Sipunculid worms 
whose fat bodies the natives deftly extract from their deep holes 
to use as bait for fish. 
In the mangrove swamp stretching from the south end of 
the mountain is the usual distinctive fauna of such a habitat ; 
the mud frequenting animals offer a special attraction as they 
are so extremely numerous. Foremost amongst these mud 
loving creatures are the crabs of bright and varied hue, the 
commonest (Uca arcuatu) being a small creature not more than 
1 or 2 inches long, resplendent in a bright blue livery. Other 
kinds are red or light brown. These pretty creatures besport 
themselves on the surface of the mud, myriads retiring at once 
to their holes when alarmed, as they retreat blocking up 
the entrance with the single huge claw. This innumerable 
army of crabs is continually scooping out holes, bringing up 
from below a semisolid mud which accumulates round the top 
of the holes and hardens in the sun. But their work is not 
enduring for with every rise of tide the mud is levelled up again. 
However in the case of one crustacean, the large mound-build- 
ing decapod Thalassina anomala, called by Malays the Enguang, 
a very profound change in the land surface is thus effected. This 
animal bores long and wide tunnels which extend from the 
liquid mud, several feet below, up to the surface of the harder 
ground above: at the surface the material brought from below 
accumulates in such quantities as to form large mounds several 
feet in height. The result is that what was formerly soft mud 
_becomes in a few days hard baked earth. This tunnelling 
moreover does not result in the formation of spacious hollows 
_ below ground as the liquid lower strata are replenished from 
the mud forming the banks of the streams. Thus it comes 
~ about that the land becomes gradually raised and this process 
continues until the thickness of the solid earth above becomes 
too great an obstacle for the enguang to penetrate. It would 
seem quite possible that the enguang when present in large 
R. A. Soc., No. 51, 1908. 
